You can also try these related scripts:

• 智慧树刷课程 - 功能:自动跳过题目,自动看下一节视频,自动调用1.5倍速!
• 智慧树挂机 - try to take over the world!
• html5 video speed controller (vlc like) - Simple html5 video speed control with '-', '+', and '=' (vlc like). '-': decrease by 0.1, '+': increase by 0.1, '=': back to 1.0x
• AnswerTip - http://tampermonkey.net/
• html5 video speed controller (vlc like) modified by Sapioit - Simple html5 video speed control with 's', 'd', and 'r'. 's': decrease by 0.25, 'd': increase by 0.25, 'r': back to 1.0x